This invention generally relates to polymers produced from the reaction of a rosin amidoamine and polyethyleneamine mixture with a multifunctional acrylate ester. More particularly, it concerns a solventless process for producing such polymers.
Tall Oil rosin is a natural product which is isolated from pine trees during the paper making process. It is mainly a mixture of cyclic, monofunctional organic acids (having 20 carbon atoms) which is a solid at room temperature (softening point of approximately 75xc2x0 C.).
It is widely used in resins for adhesives due to the adhesion it imparts. It is widely used in resins for lithographic and publication gravure inks due to the high softening point it imparts. Rosin is a minor component of alkyd resins for oil based paints when increased hardness is desirable. Rosin is a major component in low viscosity resins for thermoplastic roadmarking stripes which are applied at elevated temperatures without the use of solvent.
Monomeric rosin has not previously been used in two component systems for protective coatings, such as: (1) epoxy coatings derived from epoxy resins and amine curing agents, and (2) polyurethane coatings derived from diisocyantes and diol ether oligomers. The present invention utilizes the desirable properties imparted by rosin in other resins to form a useful polymer derived from the reaction of a rosin amidoamine/polyethylene-amine mixture with a multifunctional acrylate ester.
Polyethyleneamines such as triethylenetetramine (TETA) react very rapidly with multifunctional acrylate esters, such as trimethylolpropane triacrylate (TMPTA) via the Michael addition. However, the resulting polymers are brittle and generally lacking in strength. This reaction is highly exothermic. The exotherm can be modified by first reacting a portion of the TETA with rosin to form a rosin/TETA amidoamine. In the present invention, enough rosin is reacted with a given amount of TETA in order to achieve a product which is about 67% amidoamine and about 33% free TETA. One part of such mixture is then reacted stoichiometrically with two parts of TMPTA in a controlled-manner to form a useful polymeric protective coating.
In general aminoamide acrylate polymers and modified compositions are known in the art. The following patents are representative of such polymers and compositions.
U.S. Pat. Nos. 4,975,498, 4,987,160 and 5,155,177 to Frihart et al. disclose acrylate-modified aminoamide resins that are either thermally curable or radiation-curable.
U.S. Pat. No. 3,445,441 to Rushton discloses amino-amido polymers modified by reaction with a monoacrylate ester.
U.S. Pat. No. 4,198,331 to Buchwalter et al. discloses a curable resinous composition comprising a polyamine resin.
U.S. Pat. No. 4,675,374 to Nichols discloses certain solventless polymer compositions which are reaction products of acrylate/amine adducts and polyacrylates.
From the prior art described, there is no aminoamide acrylate polymer having the structural formula: 
where R1=rosin;
R2=dimer rosin or fatty acid dimer or R1.
There is a need in the industrial coatings area for a polymer produced by a solventless process which imparts the desirable properties of rosin.
Accordingly, it is a broad object of the invention to provide a polymer produced from the reaction of a rosin amidoamine/polyethyleneamine mixture and a multifunctional acrylate ester under controlled conditions.
Another object of the invention is to provide an amidoamine/polyethyleneamine mixture derived from the reaction of rosin with excess polyethyleneamine.
A specific object of the invention is to provide a polymer that has water and UV resistance and has good adhesion to metal surfaces.
In the present invention, these purposes, as well as others which will be apparent, are achieved generally by providing a polymer produced from the reaction of a rosin amidoamine/polyethyleneamine mixture and a multifunctional acrylate ester. The mixture can further be comprised of a dimer fatty acid and/or a rosin dimer.
Preferably the multifunctional acrylate ester is trimethylolpropane triacrylate (TMPTA).
In general, the amidoamine/polyethyleneamine mixture is derived from the reaction of rosin with excess polyethyleneamine. Preferably, the mixture contains free polyethyleneamine in an amount of approximately 33% by weight.
The invention also provides a solventless process for producing the polymer by reacting one part of the mixture with two parts of the multifunctional acrylate ester. The resulting polymer has water and UV resistance and has good adhesion to metal surfaces.
Other objects, features and advantages of the present invention will be apparent when the detailed description of the preferred embodiments of the invention are considered.
In accordance with the present invention a polymer having the following structural formula is provided: 
where R1=rosin;
R2=dimer rosin or fatty acid dimer or R1.
The polymer is produced from the reaction of component A and component B under controlled conditions. In general, component A is a rosin amidoamine/polyethyleneamine mixture and component B is a multifunctional acrylate ester. Preferably one part said component A is reacted with two parts of said component B.
In other embodiments of the invention, component A mixture is further comprised of a dimer fatty acid and/or a rosin dimer. In preferred embodiments component B is trimethylolpropane triacrylate (TMPTA), and the polyethyleneamine is triethylenetetramine (TETA).
In another alternate embodiment, component A is further comprised of a dimer fatty acid and component B is trimethylolpropane triacrylate (TMPTA).
In yet another alternate embodiment, component A is further comprised of a dimer rosin and component B is trimethylolpropane triacrylate.
In still another alternate embodiment component A is further comprised of dimer rosin and a dimer fatty acid and component B is trimethylolpropane triacrylate (TMPTA).
In all embodiments of the invention, the polymers produced have water and UV resistance and exhibit good adhesion to metal surfaces.
Both monomeric and dimeric rosins are used in the invention. Rosin is derived from pine trees (chiefly Pinus valustris and Pinus elliottii). Gum rosin is the residue obtained after the distillation of turpentine oil from the oleoresin tapped from living trees. Wood rosin is obtained by extracting pine stumps with naphtha and distilling off the volatile fraction. Tall oil rosin is a co-product of the fractionation of crude tall oil from the conventional paper making process when the wood is pulped to make paper. The principle constituents of rosin are rosin acids of the abietic and pimaric types. These acids usually have the general formula C19H29COOH with a phenanthrene nucleus.
The addition of dimer acids to the rosin/polyethyleneamine formulation has beneficial effects. Two types of dimer acids are used in the invention: (1) rosin dimers, such as Sylvatac 295 commercially available from Arizona Chemical, Panama City, Fla., and (2) fatty acid dimers, such as Sylvadym T-18, also commercially available from Arizona Chemical, Panama City, Fla. Sylvatac 295 is a mixture of monomeric and dimeric rosin acids derived from the dimerization of tall oil rosin (TOR). The dimer content of Sylvatac 295 is 35-40%. Sylvadym T-18 is a mixture of dimeric and trimeric fatty acids derived from the dimerization of tall oil fatty acids (TOFA). The dimer content of Sylvadym T-18-is 80-85%.
The invention also provides a solventless process for producing the polymer having structural formula I described above. In general, as the components are described above, component A is reacted with component B under controlled conditions to form the polymer. In the process one part component A is reacted with two parts component B under controlled temperatures.
The invention also provides an amidoamine/polyethyleneamine mixture derived from the reaction of rosin with an excess of polyethyleneamine. The excess, or free unreacted, polyethyleneamine in the mixture is approximately 33%. by weight.
In one embodiment of the invention the mixture is derived from the reaction of rosin, dimer fatty acid and polyethyleneamine.
In another embodiment of the invention the mixture is produced from the reaction of rosin, dimer rosin and polyethyleneamine.
In yet another embodiment of the invention the mixture is produced from the reaction of rosin, dimer rosin, dimer fatty acid and polyethyleneamine.
A preferred polyethyleneamine used in the invention is triethylenetetramine. In a specific process embodiment, triethylenetetramine is charged in the mixture in an amount of approximately 55%. by weight and said rosin is charged in the mixture in an amount of approximately 45% by weight.
In another embodiment triethylenetetramine is charged in the mixture in an amount of approximately 55% by weight; said rosin is charged in the mixture in an amount of approximately 40% by weight and said dimer fatty acid is charged in the mixture in an amount of approximately 5% by weight.
In another alternate embodiment triethylenetetramine is charged in the mixture in an amount of approximately 55% by weight; said rosin is charged in the mixture in an amount of approximately 29% by weight and said dimer rosin is charged in the mixture in an amount of approximately 160% by weight.
In yet another alternate embodiment triethylenetetramine is charged in the mixture in an amount of approximately 55% by weight; said rosin is charged in the mixture in an amount of approximately 26% by weight; said dimer rosin is present in the mixture in an amount of approximately 14% by weight and said dimer fatty acid is charged in the mixture in an amount of approximately 5% by weight.
The variations of the invention amidoamine/polyethyleneamine reaction mixtures are summarized in Table I below.
As illustrated further in the Examples, the polymer from the reaction of one part of REACTION MIXTURE 2 with two parts of TMPTA had the best adhesion, hardness, water resistance, UV resistance and chemical resistance as illustrated by the results in the Coatings Evaluation TABLE VII as compared to the polymers made from REACTION MIXTURES 1, 3 and 4. However, the reaction mixture of one part REACTION MIXTURE 1 and two parts TMPTA had about half the viscosity at 25xc2x0 C. versus the other reaction mixtures. See TABLE III.
REACTION MIXTURE 1 is preferred in intended applications involving extruding or spraying the reaction mixtures at elevated temperatures in a solventless form because of its lower viscosity. In spraying applications, REACTION MIXTURE 1 would be placed in one chamber and TMPTA in another. The contents of both chambers are mixed and reacted in a 1:2 ratio in the nozzle of the spray gun applicator.
The invention provides an advantage over polyurethane, epoxy, and polyester (alkyd) coatings which are all solvent based. A comparison of these protective coatings with the present invention is in TABLE II below.
TMPTA used in the invention was obtained from CPS Chemical Company and has a viscosity of 45 cps at 25xc2x0 C. This is a much lower viscosity than that of the resins used in the comparison. For example, liquid epoxy resins (EEW 190xe2x80x94epoxide equivalent weight of 190xe2x80x94such as DER(copyright)331 available from Dow Chemical or EPON(copyright)828 available from Shell) may have a viscosity of around 10,000 cps at 25xc2x0 C. The reaction mixture of one part MIXTURE 1 and two parts TMPTA has a viscosity at 50xc2x0 C. of 1,250 cps two minutes after it is mixed. Lower viscosities are obtained at higher temperatures, but such mixtures must be extruded or sprayed soon after mixing due to the rapid reactions which take place at those temperaturesxe2x80x94see Coating Evaluation TABLE IX for cure rates of MIXTURE 1/TMPTA at different temperatures.